Di Mitri, S. JACoW Geneva, Switzerland 978-3-95450-180-9 10.18429/JACoW-NAPAC2016-THPOA05 English 1104-1107 THPOA05 ion electron emittance linac quadrupole Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-NAPAC2016-THPOA05 https://jacow.org/napac2016/papers/thpoa05.pdf The role played by Intra-Beam Scattering (IBS) in high brightness electron linacs, like those driving free electron lasers, is studied analytically and with particle tracking. We found that IBS typically plays no significant role in the microbunching instability that develops in such accelerators*. A partial damping of the instability through IBS is envisaged, however, with dedicated magnetic insertions. The feasibility of linear and circular lattice designs to cumulate relevant IBS-induced energy spread, and the interplay with microbunching instability, are discussed theoretically, and with the help of tracking codes.